Our JJI-Joists offer several advantages over traditional structural timber beams, these include longer lengths, a composition that resists shrinking and warping, an excellent strength to weight ratio, straight and uniform dimensions and, uniquely, our JJI-Joists are FSC® and PAS 2050 accredited. Our JJI-Joists offer several advantages over traditional structural timber beams, these include longer lengths, a composition that resists shrinking and warping, an excellent strength to weight ratio, straight and uniform dimensions and, uniquely, our JJI-Joists are FSC® and PAS 2050 accredited.